The OEIS is supported by the many generous donors to the OEIS Foundation.
| n | a(n) |
|---|---|
| 0 | 1 |
| 1 | 2 |
| 2 | 10 |
| 3 | 84 |
| 4 | 882 |
| 5 | 10380 |
| 6 | 130916 |
| 7 | 1729960 |
| 8 | 23640770 |
| 9 | 331357276 |
| 10 | 4737405356 |
| 11 | 68818101400 |
| 12 | 1012852747220 |
| 13 | 15070913484664 |
| 14 | 226340757825800 |
| 15 | 3426481380787024 |
| 16 | 52232521742541410 |
| 17 | 801068351764540540 |
| 18 | 12351730365539402076 |
| 19 | 191363830520437179960 |
[1,2,10,84,882,10380,130916,1729960,23640770, 331357276,4737405356,68818101400,1012852747220, 15070913484664,226340757825800,3426481380787024, 52232521742541410,801068351764540540, 12351730365539402076,191363830520437179960] |